“I can’t think of any other reason that they would have vanished leaving no word for me,” I said. “So I’m afraid my next task will be to visit the hospitals and morgues in the city. Perhaps you can suggest where I should start if my friends were taken ill in this place.”

“I think I would have heard if your friends came down with poisoning,” she said. “And I heard nothing. One minute they were here and the next they were gone. Me, I still think they decided to take a jaunt and left the city. Perhaps they decided to return to New York.”

“Not leaving all their clothing behind.”

Liam squirmed and I attempted to hang onto the bag of groceries. “I must take him upstairs. He’s getting heavy.”

As I turned away she called after me. “One minute, madame. I believe a postcard might have come for you.” She reached into Sid and Gus’s mail slot and held it out to me. “I can think of no one else to whom this might apply.”

I put down the bag of groceries and took it from her. The front was a painting of a woman drinking tea. I turned it over. It was addressed in an elegant hand I didn’t recognize. I was able to translate that it was addressed “To the Lady from New York staying at 35 Rue des Martyrs.…”

The message area was left blank.

I looked up, puzzled, to see Madame Hetreau staring at me. “Is it from the American ladies?”

“No,” I said. “I’ve no idea who it is from. I don’t recognize the writing. And there’s no message. What can it mean? Did it arrive today?”

“This morning. Right after you went out.”

I held it out to her. “You’ve seen it—why would someone send me a blank postcard?”

“I have no idea, madame.”

Liam made a grab for it, and I had to hang onto him lest he tumble from my arms. “I have to take him upstairs,” I said. “Thank you for alerting me to the postcard.”

She almost hadn’t, I thought as I trudged up the stairs. She’d only handed it to me as an afterthought. Was she going to leave it hidden in the mail slot and her conscience finally got the better of her, or had she genuinely forgotten about it? As soon as I entered the apartment I put Liam in his crib, protesting loudly, and sat on the bed, turning the postcard over in my hands. Who could have known I was here and sent me a postcard? And if someone had bothered to do so, why was there no message on it?